Quoting Wang, Zhi A (2017-07-13 10:36:14) > Sorry, my bad for missing it as I only saw it used on CHV before your patch > because of some HW issue. > > Kinda of interested in the reason why HWSP CSB gains people's interest now? > :P. Anyway, it's good move to reduce the MMIO trap here.
We've been chasing the elimination of mmio reads here for the last few years, since the buffer is tantalising laid out inside a cacheline and bspec says it was designed to be read in a single cacheline load. Previously I had an alias for the CSB using ioremap_cache(), which sort-of-worked (bxt was being a little unhappy) but still required a clflush. Imagine then the surprise and delight that the information we wanted was in the HWSP ever since execlists was a twinkle in the architect's eye (back in gm45!). -Chris _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
